An optical fiber sensor has rapid response characteristics, high reliability, and a small size, and is not affected by magnetic and electric fields around the optical fiber sensor, thereby making it possible to perform accurate diagnosis and measurement. Due to these advantages, the optical fiber sensor has been applied to a technology for sensing a temperature, pressure, a chemical, displacement, current, or the like.
Particularly, as an optical fiber sensor using a surface plasmon resonance (SPR) phenomenon by a reaction between a surface of the optical fiber and surrounding environment, a gas sensor, a chemical sensor, and a bio sensor, and the like, have been in the spotlight. To this end, a technology of polishing a surface of the optical fiber, a technology of coating the optical fiber, and the like, have been applied.
Generally, the surface plasmon resonance phenomenon is a property generated by the photo-electromagnetic effect. That is, the case in which light having a specific wavelength is irradiated, a resonance phenomenon that light energy is transferred to free electrons is generated in a surface of metal nano-particles.
In the case of the optical fiber sensor using the surface plasmon resonance phenomenon according to the related art, since an optical fiber is manufactured and then metal nano-particles are deposited on a surface of the optical fiber to thereby be utilized as a sensing probe, there is a disadvantage in that secondary processing processes of the optical fiber such as a polishing process, a tapering process, a grating process, and a coating process of the optical fiber are demanded.